Self-retaining cartridge



Aug. 8, 1933. D. HoDGE SELF RETAINLNG CARTRIDGEk Filed April 15, 1929 2 Sheets-Sheet 1 Aug. 8, 1933.- D. HoDGE SELF RETAINING CARTRIDGE A Filed April 15. 1929 2 Sheets-Sheet 2 Q N Q W z 27m/Ld Hodge,

me/r V Patented Aug. 8,1933 l UNITED STATES 1,921,229 SELF-RETAINING CARTRIDGE David Hodge, Chicago, Ill., assignor to The Safety Mining Company, Chicago, Ill.,a Corporation of Illinois Application April 15, 1929, Serial No. 355,279, and in Great Britain September 18, 1928 11 Claims.

thereof forcing the cartridge either entirely out r sisting displacement of the cartridge.

of the drill hole, or to some outward position in the drill hole, whereby the force of the discharge is dissipated and the efliciency of the operation is either wholly destroyed or greatly impaired.

It is accordingly customary in present practice, to provide tamping behind the cartridge to hold it to its work, which usually consists of coal particles and dust or other materials of similar nature readily available in mines, which materials are packed in the drill hole behind the cartridge after the cartridge has been inserted and located, and tamped to form a compact holding Wad, re-

In other instances, dummies are used which are mechanical devices, usually' of metal,l adapted for insertion in the drill hole behind the cartridge and for expansion, whereby they are locked in place in a manner to serve as a substitute for the tamping above referred to.

The present invention relates to a cartridge equipped `with means as a part thereof, adapted to engage the walls of the drill hole during the discharging operation to maintain the cartridge against displacement by the blasting force, and in the present'illustration is one, the holding means of which are adapted to move outwardly and grip the walls of the drill hole with holding pressure commensurate with the force of the blasting discharge. l

Further, thev holding means under ordinary circumstances are inwardly disposed whereby they vare contained within the outside contour of the cartridge shell, and are automatically extended by the force of the blasting discharge to hold the cartridge throughout the periods during which there exists a force such as would tend to move the cartridge and after which the holding means are automatically retracted to release the cartridge, for ready recovery.

An object of this invention is to provide a cartridge having means embodied in its construction adapted to hold the cartridge against displacement in the drill hole.

Another object of this invention is to provide an improved cartridge equipped with a holding means of the above described type constructed for automatic operation by the blasting force of discharge and acting to hold the cartridge only throughout those periods during which there exists a force capable of displacing the cartridge, and during such periods holding the cartridge with a holding pressure commensurate with the force of the blasting discharge.`

The present disclosure is gif en merely by way of example and the inventio is not to be considered as limited thereby in any particular. The scope of the invention is to be determined from an understanding of the present disclosure as one embodiment thereof and an appreciation of the advantages which the invention produces in this illustrative form.

Various additional objects not specically mentioned will readily appear to one skilled in the art asthe description proceeds and the invention is fully comprehended.

The particular embodiments illustrated will be more readily understood by referring to the accompanying drawings in which:

Figure 1 is a side elevational view partly in 80 cross section of a blasting cartridge constructed in accordance with the present invention.

Figure 2 is an enlarged end elevation, partly in cross section, taken on the line 2-2 of Figure 1 and looking in the direction of the arrows. 85

Figure 3 is a view similar to Figure 2 only partly in cross section, shyving the holding means extended in the position in which they engage the drill hole walls for maintaining the cartridge in xed position.

Figure 4 is an enlarged cross sectional view of a cartridge end embodying a modified form of the present invention.

Figure 5 is a View similar to Figure 4, showing the parts in holding position.

Figure 6 is a. cross sectional end view taken on the line 6 6 of Figure 4.

By referring to Figures 1 to 3 inclusive of the drawings, it will be noted that this invention is disclosed as applied to a cartridge 10, comprisinga casing 11, a nozzle portiony 12, a rupturable end wall 13, a cap member 14, having outlet openings 15, all of the same general construction -shown in the co-pending application Serial No. 169,441, now Patent No.'1,805,541 of Helmholtz and Ferrell, 105 filed February 19, 1927.

It is to (be understood at this point, that although the present invention is disclosed as applied to thestype of cartridge shown in the copending application referred to, that it may be no applied to other forms of cartridgesirrespective of whether they employ carbon dioxide as a blasting medium. This invention depends for its operation, upon the utilization of the forces of the discharging medium for operating the locking v`means and any form of' cartridge, the bl/asting medium of which is capable of being used in the manner taught in this invention, is contemplated.

ameter as the cylinders so as to give a tight,'

sliding fit, and their outer portions reduced in l size, as at 20, and.provided with the points 21, to

serve as locking dogs when in holding engagement with the wall of the drill hole.

Surrounding the reduced portion 20, of the plungers 19, are springs 22, abutting the shoulders 23 on the plungers at one end and a locking collar or bushing 24, at its other end. The bushing 24 are screw `threaded into the outer end of the opening 17 as at 25, whereby they are held in place and in addition to serving as an abutment for the spring 22, they provide a bearing surface 26, for the outer reduced end 20, of the plungers 19. Surrounding the base portion of the plungers 19 are sealing rings 27 which serve to prevent the outward escapement of gas.

As shown in Figure 2, the wall of coal 30, is provided with a drill hole 31, of substantially'the same diameter as the diameter of the blasting cartridge so that the cartridge may be inserted longitudinally therein until it Ahas been located at the position at which it is desired for the blasting operation. During the inserting operation, the springs 17,- which are expanding springs, serve to force the plungers inwardly, whereby the outer points 21 are disposed within the outer contour of the cartridge shell. While the plungers are in this position, they oier no resistance to the inward movement of the cartridge in the drill hole.

Upon discharge of the cartridge, it will be obvious that the lxed outward rush of expanding gas will, in addition to passing outwardly through the outlet opening 15, rapidly flnd its way into' the opening 16 and ducts 18 and finally into the cylinders 17, where it will act to move the plungers 19, radially outwardly against the tension of the springs whereby to cause the outer points 21 to rapidly and forcefully engage the surrounding wall portions of the drill hole, and to maintain the plungers and locking dogs in the locking position as well, as expanding pressure or discharging force of the f gas continues to exert any force which would tend to displace the cartridge outwardly of the drill hole.

In the modication illustrated in Figures 4 to 6 inclusive, a modified form of cap 40 is employed, having the threaded end 4l by which it is secured to the main cylinder of the cartridge as shown in Figure l. The cap is provided with outlet openings 42 corresponding to the openings 15 in the other modification.

The holding mechanism is operated however, by means of a piston 43 which is exposed to the pressure of the vdischarging gases instead of being operated'directly by the gases communicated through the small ducts 18 as shown in Figure 3, for instance.

The piston 43 is slidingly mounted in a central opening 44 which is closed at its outer endl by means of the screw plug 45. The piston is prov'ided with a head 46 having a cushion washer 47 g around the edge thereof in a manner to cushion the contact between the head and the end of the cap wall.

A packing ring 48 is provided to prevent the passage of gas between the. piston and cylinder wall. A plurality of grooves 49 having inclined bottom surfaces/50 are provided on the end of the piston and constructed to receive the ends 51 of the plungers 52. The plungers are mounted in radially disposed cylinders 53, formed by the bushings 54, screw threaded in the radial openings 55 provided in the outer surface of the cap. The ends 56 of the plungers are slightly cupped as shown, to provide a sharp knife edge adapted for forming holding contact with the wall portion of tl drill hole.

The plungers are normally urged inwardly by means of the spring 57, mounted in substantially the same manner as that shown in connection with`the other modification. The ends 51 of the plungers are provided with inclined end surfaces 58, constructed for cooperation with the inclined surfaces 50 of the'piston. By this arrangement, it will be observed that the inward movement of the piston causes the radial outward movement of each of the plungers. Mounted in the end plunger, is the end plate, 59, screw threaded in the socket as at 60. This end plate is of such size that in the position shown in Figure 4, it overlaps the ends 51 of the plungers whereby an abutment is formed preventing excessive outward movement of the piston 43.

The piston is urged in its outward direction by means of the spring 61, in engagement with the piston at one end, and with the screw plug 45 at its other end.

Inyoperation under ordinary circumstances, the parts of the holding mechanism will be arranged in position as shown'in Figure 4, the parts being forced to assume these positions by means of the various springs. While in` this position, it will be noted that the plungers are disposed inwardly so that they occupy spaces wholly within the confines of the cartridge and in this respect offer n o projecting parts such as would prevent the insertion of the cartridge in the drill hole.

When the cartridge is inserted and discharged, the gas passing outwardly making its way to the radial outlet opening 42, will rst impinge upon the head 46 of the piston and drive it outwardly against the opposition of the spring 61. In moving outwardly, the cooperating surfaces 50 and 58 on the piston and plungers respectively. will cause the plungers to move radially outwardly to the position shownin Figure 5 in which position the ends of the plungers are urged .and held in intimate holding engagement with the wall of the drill hole.

Here, like in the other modiflcation, the holding .force is commensurate with the discharging pressure or in other words, the pressure which exerts a tendency to displace the cartridge axially in the drill hole. The contact between the head 46 of the piston and the cooperating wall portion of the cap is cushioned by means of the washer tion. As above mentioned, the outward position of the piston is limited by means of the cap member 59 coming in contact with the edges of the ends 51 of the plungers.

It will also appear that the holding force of the locking dogs is commensurate with the discharging force whereby the greater the tendency to displace the cartridge, the more firmly the cartridge is held.

When the expanding force is entirely or nearly dissipated, the stored energy in the springs associated with the plungers will cause them to overcome the pressure of the gas and to restore the plungers to their inward position whereby the dogs are released from their holding engagement and are brought to a position entirely within the outer connes of the cartridge.

It will appear from this description that the present embodiments accomplish all of the foregoing objects and further that the construction is simple and eilicient and one which is contained wholly within the cartridge without any projecting parts such as would interfere with normal operations, be subject to damage or otherwise cause trouble.

In the present disclosure, it is to be understood that the cartridge 12 contains in addition to a blasting medium, suitable heating means and electrical connections therefor, all of which are fully shown and described in the co-pending application referred to and which by reason of their description in the copending application are not shown or described here.

This invention is not to be limited by the present disclosure but the scope thereof is to be determined by referring to the appended claims.

I claim:

1. A cartridge of the character described comprising a discharge passage, a normally retracted locking dog, and means extending between said dog and discharge passage, arranged to utilize the pressure of the expanding gases upon discharge in a manner to move saidlocking dog outwardly.

2. A blasting cartridge having in combination, a cylinder, a plunger in said cylinder, an anchor element on the outer end of said plunger, a gas discharging passage, anda communication between said passage and the base of said cylinder.

3. A blasting cartridge having in combination, a cylinder, a plunger in said cylinder, an anchor element on the outer end of said plunger, a gas discharging passage, and a communication betu een said passage and the base of said cylinder and means for urging said plunger toward the base of said cylinder.

4. A blasting cartridge having in combination, a cylinder, a plunger in said cylinder, an anchor element on the outer end of said plunger, a gas discharging passage, and a communication between said passage and the base of said cylinder and gas sealing means on said plunger.

5. A blasting cartridge having means for holding said cartridge against displacement, said means being normally disposed wholly within the confines of said cartridge and capable of extending to engage the Walls of a drill hole.

6. A blasting cartridge having in combination a cylinder, a plunger in said cylinder having a contact holding end, a piston responsive to the pressure of discharging gases, and means connecting said plunger for operation by said piston.

7. A blasting cartridge having in combination a cylinder, a plunger in said cylinder having a contact holding end, a piston located in said cartridge having an end exposed to the pressure of discharging gases, and mechanical connecting means between said plunger and piston.

8. A blasting cartridge having in combination a cylinder, a locking plunger mounted on said cylinder mounted for radial movement, a longitudinally disposed piston in said cylinder having an end exposed to the discharging pressure and a cam surface adjacent its other end, and cooperating cam means on said plunger in engagement with said first named cam means.

9. The combination with a blasting cartridge having an aperture thru which discharge gases are directed to perform the intended blasting operation, Aof means embodied in said cartridge and positioned adjacent said aperture to be actuated by the discharge gases into anchoring position.

10. The combination with a blasting cartridge comprising a hollow body having a discharge aperture, a rupturable member closing said aperture, a discharge cap having adjustable connection with said body and engaging said rupturable member for maintaining same in sealed relation with said aperture, of means embodied in said discharge cap adapted to be actuated by gases discharged through said aperture into said cap for anchoring said cartridge.

11. A blasting cartridge embodying means for developing a blasting pressure therewithin, and means for holding said cartridge against displacement normally being disposed wholly within the connes of said cartridge and capable of being extended to engage the wall of adrill hole by pressure within the cartridge.

DAVID HODGE. 

